The present invention relates to oscillator circuits suitable for being used as a signal generator, for instance a timer, a clock circuit, a sensor for detecting such various physical values as displacement or revolution of an object, and the like. The present invention is more particularly concerned with an improvement of an oscillator circuit in which a variable capacitor cooperates with a resistor to conduct oscillation in the oscillator circuit at a frequency proportional inversely to the product of a capacitance of the capacitor and a resistance value of the resistor.
To enhance the sensitivity of such a conventional oscillator as described above, it is required to expand a range of the oscillating frequency as wider as possible. For this requirement, however, a capacitor of a large capacitance must be utilized as the variable capacitor, and this results in an enlarged construction of the oscillator circuit due to the larger size of the capacitor, causing various undesirable problems in actual use of the oscillator circuit.